One of Superman's foes. He is supposedly Earth-One's 1st super-criminal.
Lewis Pagett was a turn of-the-20th century scientist who discovered how to give himself super powers using microwaves, which at the time where only beginning to be used for broadcasts. Creating the costumed identity of Microwave Man, he committed a few robberies, with the police helpless to stop him (and no superheroes had appeared yet.) However just as fast as he appeared, he disappeared.
The reason for this was because his experiments attracted the attention of aliens, who invited him to see the galaxy with them, and he accepted. Now an old man, they finally brought him back to Earth so he could die here. However when he discovers the existence of Superman (and that his powers have increased a millionfold due to how much more microwaves are used in the present) he asks the aliens to restore his youth so he can experience the thrill of a fight with Superman, even though he knows the strain will kill him. They agree.
During the fight, Superman comes up with a way to defeat him: taking him back in time to before his powers were so mighty (this was back when Superman could time travel.) However he ends up not using this trick, and in fact Pagett defeats him- and then dies. This is because the aliens contacted Superman mid-battle and told him about his imminent death. They then claimed his body and left Earth.
-Microwave Man should not be confused Blackrock, another radiowave-powered Superman foe.
-This is Microwave Man's only appearance ever. Presumably he never existed in the Post-Crisis universe.
-Although not stated, the aliens in this story *might* have been the same ones from "The Amazing Return of Johnathan Kent" from Action Comics #508 because they had a very similar UFO. However the aliens themselves are never seen (in either story.) It could just be that the artist happened to like that particular design.